Document Type

Technical Report

Date of this Version

2-1999

Publication Source

The Plant Cell

Volume

11

Issue

2

Start Page

207

Last Page

221

DOI

10.1105/tpc.11.2.207

Abstract

Lesions in brassinosteroid (BR) biosynthetic genes result in characteristic dwarf phenotypes in plants. Understanding the regulation of BR biosynthesis demands continued isolation and characterization of mutants corresponding to the genes involved in BR biosynthesis. Here, we present analysis of a novel BR biosynthetic locus, dwarf7 (dwf7). Feeding studies with BR biosynthetic intermediates and analysis of endogenous levels of BR and sterol biosynthetic intermediates indicate that the defective step in dwf7-1 resides before the production of 24-methylenecholesterol in the sterol biosynthetic pathway. Furthermore, results from feeding studies with 13C-labeled mevalonic acid and compactin show that the defective step is specifically the Δ7 sterol C-5 desaturation, suggesting that dwf7 is an allele of the previously cloned STEROL1 (STE1) gene. Sequencing of the STE1 locus in two dwf7 mutants revealed premature stop codons in the first (dwf7-2) and the third (dwf7-1) exons. Thus, the reduction of BRs in dwf7 is due to a shortage of substrate sterols and is the direct cause of the dwarf phenotype in dwf7.

Copyright/Permission Statement

© 1999 American Society of Plant Physiologists. Reproduced with permission.

Comments

At the time of this publication, Dr. Gregory was affiliated with the University of Arizona, but he is now a faculty member at the University of Pennsylvania.

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Date Posted: 14 July 2017

This document has been peer reviewed.